Wireless communication networks typically provide a number of different services, such as voice and data communication services. Most wireless communication networks typically offer a single type of voice communication service, interconnect voice communication services (also referred to as circuit-switched voice communication services). Interconnect voice communication services provide a full-duplex communication between two communication endpoints.
Another type of voice communication service is push-to-talk voice communication service (also referred to as dispatch communication service), which involves a half-duplex communication between two communication endpoints. Thus, a push-to-talk call requires flow control to ensure that only one endpoint has permission to talk at any particular time during the call. There are three basic types of push-to-talk calls, call alerts, private calls and group calls. Call alerts merely inform the caller whether the called party is available for a call, but no voice channel is established. Private calls involve establishing a voice channel between two endpoints, whereas group calls involve establishing a voice channel between more than two endpoints.
Push-to-talk communication services have historically been employed in private wireless communication networks by, for example, taxi cab companies or emergency service agencies (e.g., police and fire departments). Until recently, the only type of public wireless communication network that supported push-to-talk calls was the iDEN network, such as the one owned and operated by Sprint Nextel Corporation.
One of the most recognized advantages of push-to-talk calls compared to interconnect calls is the fast call setup time. For example, push-to-talk calls are typically setup in less than one second, whereas interconnect calls may not even begin to ring the called party in this time. Private wireless communication networks and the iDEN network are able to provide push-to-talk calls with a fast setup time because these networks are specifically designed to provide these types of calls.